Yarn retarding device

ABSTRACT

A retarding device surrounding a storage drum adapted to have yarn wound tangentially thereon and unwound axially therefrom. The retarding device comprises a coiled spring whose opposite ends are secured to form a continuous retarding ring having an inner contour smaller than the outer contour of the drum before the ring is mounted on the drum whereby the ring is placed under tension when mounted on the drum. Each coil of the spring has a curved portion in bearing engagement against the drum which defines a constant resistance to the yarn which passes thereunder as it is axially withdrawn from the drum.

United States Patent [1 1 Schussel 51 Mar. 11, 1975 I 1 YARN RETARDINGDEVICE [73] Assignee: Wesco Industries, Corporation,

Plainview, N.Y.

221 Filed: Apr. 22, 1974 [21] Appl. No.: 463,099

52 us. Cl 242/47.01, 242/47.12, 242/147 R 511 int. Cl B65h 51/20 581Field of Search 24214101 4713, 147 R,

3,702,176 11/1972 Rosen 242/47.01 3,713,307 l/1973 Muhlhausler 242/47.01X 3,780,958 12/1973 Deniega et a1 242/47.12

Primary Examiner-Stanley N. Gilreath Attorney, Agent, or Firml-lenry R.Lerner [57] ABSTRACT A retarding device surrounding a storage drumadapted to have yarn wound tangentially thereon and unwound axiallytherefrom. The retarding device comprises a coiled spring whose oppositeends are secured to form a continuous retarding ring having an innercontour smaller than the outer contour of the drum before the ring ismounted on the drum whereby the ring is placed under tension whenmounted on the drum. Each coil of the spring has a curved portion inbearing engagement against the drum which defines a constant resistanceto the yarn which passes thereunder as it is axially withdrawn from thedrum.

4 Claims, 3 Drawing Figures YARN RETARDING DEVICE BACKGROUND OF THEINVENTION The present invention relates to means for controlling theaxial withdrawal of yarn or filament which has been wound about a drumor bobbin.

The invention has particular application to yarn storage and feedingdevices, such as shown in U.S. Pat. Nos. 3,225,446, 3,419,225 and3,780,958, the last mentioned patent being assigned to the assigneehereof. Each of the storage devices shown in the aforementioned patentsincludes a storage drum about which yarn is wound tangentially either byrotation of the drum or rotation of a winding element about the drum toform on the drum a number of windings which are stored for subsequentaxial withdrawal as demanded by the textile producing machine.

It is highly desirable to control the tension of the yarn beingwithdrawn from the storage drum by using a retarding element whichengages the yarn as it is withdrawn endwise of the drum. In U.S. Pat.No. 3,225,446, the retarding means comprises an ordinary resilient bandplaced about the drum so that the yarn which is withdrawn passes betweenthe resilient band and the drum and has imparted thereto a retardingforce. Such arrangement is not very satisfactory because the tension ofthe yarn being withdrawn cannot be accurately controlled and becausevariations in tension do occur causing a lack of uniformity in thearticle produced by the textile machine.

Another form of retarding element which avoids the problems inherent inthe use of a conventional resilient band is that shown in U.S. Pat. Nos.3,648,939 and 3,702,176 wherein the retarding element comprises aplurality of flexible elements formed by resilient fingers which areinclined inwardly from a base ring along an imaginary conical surfaceand extend in the direction of relative rotation of the yarn during itswithdrawal from the drum. The outerends of the resilient fingers aresecured to a base ring which is greater in diameter than the portion ofthe drum it surrounds, and the inner ends of these fingers, which may becurved, lie in a circle which is smallerthan the radius of the drum sothat these inner ends bear against the surface of the drum. The yarnwhich is withdrawn must pass from under one finger to under the next andovercome a relatively constant resistance during withdrawal, so thatsuch retarding ring does perform satisfactorily. On the other hand, suchretarding ring, being formed of plastic by molding, is relatively costlyand fragile, rendering such ring somewhat less than wholly satisfactoryfor its intended purposes.

The present invention has as its object the provision of a retardingmeans which retains all of the advantages of the retarding rings inaforementioned U.S. Pat. Nos. 3,648,939 and 3,702,176, while having noneof its disadvantages.

SUMMARY OF THE INVENTION In accordance with the invention, the retardingdevice is obtained by using a conventional coiled or helical springwhich has been partially flattened so that the windings of the springare angularly related with respect to the longitudinal axis of thespring when the latter is in relaxed condition. The free ends of thespring are then secured to each other to form an endless spring having agenerally circular configuration. In its free condition, the innercontour of the endless spring is smaller than the contour of the drum.Accordingly, the spring must be expanded for placing it, onto the drum,and once on the drum, the tension on the spring will cause the latterscoils to bear against the surface of the drum. This arrangement enablesthe coils of the endless spring to firmly bear against the drum so thateach of these coils defines a constant resistance to the yarn which mustpass thereunder as it is axially withdrawn from the drum.

Since the endless spring has been partially flattened as aforedescribed,each individual coil thereof is angularly related with respect to aradius of the drum passing through the contact portion of coil and drum,in the direction of relative rotation of the yarn during its withdrawalfrom the drum, which contact portion is curved. It is apparent that theendless helical flattened spring, which defines the retarding element inaccordance with the invention, can be formed so as to meet any specifiedyarn tension requirements. More specifically, the length or averagecontour of the spring, the number of windings per unit of length, thewire diameter, the diameter of the windings, and the angularity of thewindings relative to the spring contour, can be preselected so as toprovide the retarding characteristics which may be desired. Thus, allthe advantages of the prior art retarding means are retained in theinvention while at the same time providing these advantages with greaterflexibility and at a reduced cost.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a perspective view of astorage feeder, with parts broken away, and having mounted thereon theyarn retarding means in accordance with the invention;

FIG. 2 is a top plan view of the storage feeder drum shown in FIG. 1, onan enlarged scale; and

FIG. 3 is an elevational view of the portion of the spring and drumwithin area 3 of FIG. 1, on an enlarged scale.

DESCRIPTION OF THE PREFERRED EMBODIMENT Referring now to the drawings,storage feeding device 10 (similar to that shown in aforementioned U.S.Pat. No. 3,780,958) is provided with a drum 12 fixed against rotation,and a yarn winding member 14 adapted to rotate about drum 12 formingthereon a plurality of yarn windings which advance towards the free endof the drum, which stored yarn is axially withdrawn from the drum asintermittently demanded by a textile producing machine, such as aknitting machine, as fully described in aforementioned U.S. Pat. No.3,780,958, assigned to the assignee hereof.

In accordance with the invention, there is provided adjacent the freeend of drum 12 and in surrounding relation thereto retarding means 16which applies a retarding force to the axially withdrawn yarn whichpasses between the retarding means 16 and the drum as it is withdrawnfrom the drum.

As best shown in FIGS. 2 and 3, retarding means 16 comprises a helicalspring 18 whose free ends have been secured together to define anendless spring of related with respect to the longitudinal extent of thespring, before the free ends thereof are secured to form the endlessgenerally circular shaped spring.

In the free condition of the endless spring 18, the inside diameter orcontour of the spring is smaller than the outside diameter or contour ofdrum 12 so that spring 18 must be expanded before placing it onto thedrum 12. When positioned on drum 12, as shown in FIG. 2, the id or innercontour of the expanded spring will, of course, coincide with the o.d.or outer contour of drum 12. The necessary spring expansion for enablingspring 18 to be placed on the drum causes the individual windings of thespring to bear against the surface of the drum.

The angularity of the windings created by the flattening of the springenables the winding portions P which are engaged by the withdrawing yarnto extend in the direction of relative rotation of the yarn during itswithdrawal as shown in FIG. 2, such being desirable for impartinguniform non-jerky retarding forces to the yarn being withdrawn. Morespecifically, portion P of each winding, which is curved, is inclinedwith respect to a radial line passing through P forming an angle arelative thereto which may be varied within a range extending from to 50to obtain lesser or greater inclination as may be desired.

It is apparent that the retarding force applied by spring 18 to the yarnbeing withdrawn from the drum depends on the several parameters ofspring 18. More specifically, the id. or inner contour of the endlessspring must be smaller than the o.d. or outer contour of the storagedrum. As the difference between the two contours increases, the forcebearing against the drum by the independent windings, which must besurmounted by the withdrawing yarn, also increases. Also influencing thecharacteristics of the retarding force are the diameter of the wireforming the spring windings as well as the diameter of the windingsthemselves.

What is clearly evident is that all the parameters of spring 18 abovedescribed, including the angularity of the spring windings, can bepreselected as desired to meet any required condition of operation asaffected by the type of yarn being utilized and the nature of thetextile producing machine receiving the yarn. The yarn being withdrawn,it is clear, is confronted by a plurality of spring coil portions whichare curved and which are inclined in the direction of relative rotationof the yarn during its withdrawal from the drum, all of which fea turesprovide the highly desirable control for the yarn.

It is well recognized that a storage feeding device of the type referredto herein is subjected to a wide variety of different yarns fordifferent applications, each of which variations may require a retardingmeans having different characteristics making it necessary to have aplurality of retarding means normally available, which is costly. Thiscost element is substantially reduced where the retarding means is ametal spring which can be made inexpensively as is the case inaccordance with the invention, especially as compared to the prior artin which the retarding means is a fragile plastic molded element.

As the yarn passes under spring 18, the latter may have a tendency to beaxially displaced, especially in an application where the spring isunder little tension in order to provide a relatively small retardingforce. Such axial displacement may therefore be prevented by providing ashoulder on the drum as in aforementioned U.S. Pat. No. 3,648,939. Whilesuch shoulder is the sole means effective for preventing axialdisplacement in said patent, this is not the case in accordance withspring 18 of the present invention. More specifically, since spring 18can be made of steel, the portion of drum 12 adapted to be surrounded byspring 18 may be suitably magnetized for retaining the spring thereonand prevent axial displacement thereof, dispensing with the need of ashoulder.

While the retarding means in accordance with the present invention hasbeen described in association with a storage feeding device, it will beunderstood that it is equally applicable to control yarn axiallywithdrawn from any storage member onto which yarn has been wound,whether or not such storage member is part of a storage feedingdevice.

While there is herein shown and described the preferred embodiment ofthe invention, it will be understood that the invention may be embodiedotherwise than as herein specifically illustrated or described, and thatin the illustrated embodiment certain changes in the details ofconstruction and in the form and arrangement of parts may be madewithout departing from the underlying idea or principles of thisinvention within the scope of the appended claims.

Having thus described my invention, what I claim and desire to secure byletters patent is:

1. In a yarn storage device having a storage drum adapted to have yarnwound tangentially thereon and unwound axially therefrom, a retardingdevice surrounding said drum and adapted to have said yarn passedthereunder as it is axially withdrawn, said retarding device comprisinga coiled spring whose opposite ends are secured to each other to form acontinuous retarding ring having an inner contour smaller than the outercontour of said drum before said ring is mounted on said drum, wherebysaid ring is placed under tension when mounted on said drum, each coilof said spring having a curved portion in bearing engagement againstsaid drum which defines a constant resistance to the yarn which passesthereunder as it is axially withdrawn from the drum.

2. The improvement in accordance with claim 1, wherein said coiledspring is partially flattened whereby the curved portion of each coil isinclined with respect to a radius of said drum passing through the pointof engagement of said curved portion and said drum.

3. The improvement in accordance with claim 2, wherein the curvedportion of each coil is inclined in the direction of relative rotationof the yarn during its withdrawal from the drum.

4. The improvement in accordance with claim 3, wherein the angle ofinclination of the curved portion of each coil is between 10 and 50 withrespect to said drum radius.

1. In a yarn storage device having a storage drum adapted to have yarnwound tangentially thereon and unwound axially therefrom, a retardingdevice surrounding said drum and adapted to have said yarn passedthereunder as it is axially withdrawn, said retarding device comprisinga coiled spring whose opposite ends are secured to each other to form acontinuous retarding ring having an inner contour smaller than the outercontour of said drum before said ring is mounted on said drum, wherebysaid ring is placed under tension when mounted on said drum, each coilof said spring having a curved portion in bearing engagement againstsaid drum which defines a constant resistance to the yarn which passesthereunder as it is axially withdrawn from the drum.
 1. In a yarnstorage device having a storage drum adapted to have yarn woundtangentially thereon and unwound axially therefrom, a retarding devicesurrounding said drum and adapted to have said yarn passed thereunder asit is axially withdrawn, said retarding device comprising a coiledspring whose opposite ends are secured to each other to form acontinuous retarding ring having an inner contour smaller than the outercontour of said drum before said ring is mounted on said drum, wherebysaid ring is placed under tension when mounted on said drum, each coilof said spring having a curved portion in bearing engagement againstsaid drum which defines a constant resistance to the yarn which passesthereunder as it is axially withdrawn from the drum.
 2. The improvementin accordance with claim 1, wherein said coiled spring is partiallyflattened whereby the curved portion of each coil is inclined withrespect to a radius of said drum passing through the point of engagementof said curved portion and said drum.
 3. The improvement in accordancewith claim 2, wherein the curved portion of each coil is inclined in thedirection of relative rotation of the yarn during its withdrawal fromthe drum.